The present invention relates to functionalized cyclopentene-derived oligomer mixtures, processes for their preparation by hydroformylation and, where appropriate, further reaction of corresponding oligomer mixtures which contain ethylenic double bonds, and their use.
The processing of petroleum by steam cracking results inter alia in a hydrocarbon mixture which is called the C5 cut and has a high total olefin content of, for example, about 50%, of which about 15% is made up of cyclopentene and the remainder of acyclic monoolefins, especially n-pentene (about 15% by weight) and other isomeric pentenes (about 20% by weight). This mixture can, if required, before further processing be subjected to partial catalytic hydrogenation so that dienes are essentially no longer present then. To isolate the cyclopentane which comprises about 8% of the C5 cut and which is employed, for example, as propellent as substitute for the CFCs and HFCs which are of concern with regard to damage to the atmosphere, and where appropriate to isolate the other saturated acyclic pentanes, it is necessary in the prior art to subject the C5 cut to work up by distillation. This is technically a very complicated process when acyclic and cyclic C5 olefins, in particular cyclopentene, are simultaneously present. There is thus a need for a process for removing cyclopentene and, where appropriate, other monoolefins from the C5 cut other than by distillation, where possible with simultaneous production of a new product of value.
It is possible for this purpose to subject the C5 cut to a metathesis reaction in the presence of a transition metal catalyst, resulting in new cyclopentene-derived oligomer mixtures with ethylenic double bonds.
A known process for the functionalization of polymers with ethylenic double bonds is hydroformylation. Thus, for example, M. P. McGrath et al., describe, in J. Appl. Polym. Sci. 56, (1995) 533 et seq., the hydroformylation of EPDM polymers and polybutadienes with HRhCO(PPh3)3 or Rh(CO)2acac (acac=acetylacetonato) as hydroformylation catalysts in toluene. Reviews on the hydroformylation of polymers with olefinic double bonds, such as polyisoprene or styrene/butadiene copolymers, are given by N. T. McManus et al. in J. Macromol. Sci., Rev. Macromol. Chem. Phys. C35(2) (1995) 239-285.
Aldehyde-functionalized polymers of this type in turn permit reactions to be carried out on the polymer, ie. conversion into or attachment of new functionalities which confer new properties on the polymer.
C. Azuma et al. describe in J. Polym. Sci., Polymer Chemistry Edition, 18, (1980) 781 et seq. the hydroformylation of a polypentenamer with a number average molecular weight of 94,000 in the presence of an HRhCO(PPh3)3 catalyst, and the subsequent conversion into the oxo alcohols with various reducing agents such as sodium borohydride. The amounts of catalyst needed for this hydroformylation are extremely high at about 5000 ppm. Hydroformylation of the polymer is possible only to a maximum aldehyde content of 30 mol %, otherwise insoluble products result. It is likewise necessary for the hydroformylated polymers to be reacted further immediately, without isolation, otherwise crosslinking occurs, likewise resulting in completely insoluble products.
K. Weissermel, H. J. Arpe, Industrielle Organische Chemie, 4th edition, 1994, VCH Weinheim, pages 137 et seq. describe the hydroformylation (oxo synthesis) of olefins by reaction with carbon monoxide and hydrogen in the presence of a catalyst and generally at elevated temperatures under elevated pressures. The oxo aldehydes obtained therefrom have virtually no importance as final products but are important reactive intermediates for preparing oxo alcohols, oxo carboxylic acids and aldol condensates. It is furthermore possible for oxo aldehydes to be converted by reductive amination with ammonia or a primary or secondary amine in the presence of a reducing agent into the corresponding amines.
The oxo alcohols can in principle be prepared together with the hydroformylation, usually at elevated temperature, in a one-stage synthesis because the hydroformylation catalysts are generally also suitable for further hydrogenation of the oxo aldehydes. However, the oxo aldehydes are usually first isolated and then subjected to a catalytic hydrogenation on a specific hydrogenation catalyst selected from metals in group VIII or Ib, eg. a Cu or Ni catalyst.
To prepare oxo carboxylic acids, the oxo aldehydes can be oxidized with mild oxidizing agents, in the simplest case with air or with H2O2 in the presence of acids. The oxidation with air can take place either catalytically in the presence of metal salts or else in the absence of catalysts at up to about 100xc2x0 C. under pressures up to about 7 bar.
Houben-Weyl, Methoden der organischen Chemie, Volume XI/1, 1957, pages 602 et seq., describes the reduction of condensates of ammonia or amines and carbonyl compounds, and the reductive amination of carbonyl compounds, the latter, eg. an aldehyde, being reacted with ammonia or a primary or secondary amine in the presence of a reducing agent without isolation of an intermediate. The reducing agent generally used is hydrogen in the presence of a hydrogenation catalyst, but it is also possible to use other reducing agents, such as formic acid and its derivatives. None of the abovementioned publications refers to a process for functionalizing oligomers derived from cyclopentene and obtainable by a metathesis reaction of the C5 cut from petroleum processing.
It is an object of the present invention to provide a process for further processing of the new oligomer mixtures produced by a metathesis reaction on the C5 cut.
We have found that this object is achieved by a process for preparing functionalized cyclopentene-derived oligomer mixtures, where the cyclopentene-derived oligomer mixtures which contain ethylenic double bonds are subjected to a hydroformylation and, where appropriate, further functionalizations.
The invention thus relates to a process for preparing functionalized cyclopentene-derived oligomer mixtures by a single stage or multistage functionalization of at least some of the ethylenic double bonds present in an oligomer mixture of the formula I
R1R2CCHxe2x80x94(CH2)3xe2x80x94CHnCR3R4xe2x80x83xe2x80x83(I)
where n is an integer from 1 to 15, and R1, R2, R3 and R4 are, independently of one another, hydrogen or alkyl.
The value of n in the formula I is the number of cyclopentene units introduced by a ring-opening metathesis reaction into the cyclopentene-derived oligomer mixtures. The oligomer mixtures of the formula I preferably used for the process according to the invention are those where the value of n is  greater than 1 in a proportion which is as large as possible, eg. at least 40% by weight (determined by integration of areas in the gas chromatograms). The value of n and thus the extent of the ring-opening metathesis can be influenced by the activity of the metathesis catalyst used and the ratio of acyclic to cyclic olefins.
The radicals R1, R2, R3 and R4 in the formula I are, independently of one another, hydrogen or alkyl, where the term xe2x80x9calkylxe2x80x9d embraces straight-chain and branched alkyl groups.
These are preferably straight-chain or branched C1-C15-alkyl, preferably C1-C10-alkyl, particularly preferably C1-C5-alkyl, groups. Examples of alkyl groups are, in particular, methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,2-dimethylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,3-dimethylbutyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethylbutyl, 2-ethylbutyl, 1-ethyl-2-methylpropyl, n-heptyl, 1-methylhexyl, 1-ethylpentyl, 2-ethylpentyl, 1-propylbutyl, octyl, decyl, dodecyl, etc.
The degree of branching and the number of carbon atoms in the terminal alkyl radicals R1, R2, R3 and R4 depend on the structure of the acyclic monoolefins in the hydrocarbon mixture used and on the activity of the catalyst. The activity of the catalyst also influences the extent of cross-metathesis (self-metathesis) of the acyclic olefins to form olefins which have novel structures and into which cyclopentene is then formally inserted in a ring-opening metathesis polymerization.
The oligomer mixtures of the formula I used according to the invention for the functionalization are obtainable by a metathesis reaction of hydrocarbon mixtures comprising acyclic and cyclic olefins.
Preferably used is a hydrocarbon mixture which results from the industrial processing of petroleum and which can, if required, be subjected beforehand to a partial catalytic hydrogenation to remove dienes. A particularly suitable example is a mixture (C5 cut) which is enriched in saturated and unsaturated C5 hydrocarbons. The C5 cut can be obtained, for example, by subjecting the pyrolysis gasoline produced in the steam cracking of naphtha firstly to a selective hydrogenation, in order to convert the dienes and acetylenes present therein selectively into the corresponding alkanes and alkenes, and then to a fractional distillation, resulting in the C6-C8 cut, which is important for further chemical syntheses and which contains the aromatic hydrocarbons, as well as the C5 cut used for the process for preparing the oligomer mixtures of the formula I.
The C5 cut generally has a total olefin content of at least 30% by weight, preferably at least 40% by weight, in particular at least 50% by weight.
Suitable C5 hydrocarbon mixtures in this connection are those with a total cyclopentene content of at least 5% by weight, preferably at least 10% by weight, in particular at least 12% by weight, and in general not more than 30% by weight, preferably not more than 20% by weight.
Furthermore, the proportion of pentene isomers in the acyclic monoolefins in suitable C5 hydrocarbon mixtures is at least 70% by weight, preferably at least 80% by weight, in particular at least 90% by weight.
Preferably used for preparing the oligomer mixtures of the formula I is a C5 cut produced industrially with a total olefin content of, for example, 50 to 60% by weight, such as about 56%, a cyclopentene content of, for example, 10 to 20%, such as about 15% by weight, and a pentene isomer content of, for example, 33 to 43% by weight, such as about 38% by weight, consisting of about 16% by weight n-pentene and about 22% by weight isomeric pentenes.
It is also possible furthermore to use a hydrocarbon mixture which comprises the C5 cut and a petroleum fraction containing acyclic C4 olefins (distillate 2) or the C5 cut and ethene.
The metathesis reaction of the hydrocarbon mixture comprises
a) disproportionation of the acyclic monoolefins in the hydrocarbon mixture (C5 cut) by cross-metathesis,
b) oligomerization of the cyclopentene by ring-opening metathesis,
c) chain termination by reaction of the oligomers from b) with an acyclic olefin in the hydrocarbon mixture or a product from a), where steps a) and/or b) and/or c) may take place more than once on their own or in combination.
Step a)
Combinations of cross-metathesis of different, and self-metathesis of identical, acyclical olefins, and repetition of this reaction, result in a large number of monoolefins which differ in structure and number of carbons and which form the end groups of the oligomers of the formula I. The double bond content of the oligomers is also influenced by the proportion of cross-metathesis products, which increases with increasing activity of the catalyst used. Thus, for example, ethene is liberated in the self-metathesis of 1-pentene and may, where appropriate, escape as gas, which removes one double-bond equivalent from the reaction. At the same time there is an increase in the proportion of oligomers without terminal double bonds.
Step b)
The average number of cyclopentene insertions into the growing chain in the form of a ring-opening metathesis polymerization determines the average molecular weight of the cyclopentene oligomer mixture of the formula I which is formed. The average molecular weight of the oligomer mixtures of the formula I formed by the process according to the invention is preferably at least 274, which corresponds to an average number of three cyclopentene units per oligomer.
Step c)
Chain termination takes place by reaction of an oligomer which still has an active chain end in the form of a catalyst complex (alkylidene complex) with an acyclic olefin, with, in the ideal case, an active catalyst complex being recovered. The acyclic olefin in this case may be derived unchanged from the hydrocarbon mixture originally employed for the reaction, or have been previously modified in a cross-metathesis in stage a).
Suitable catalysts for the metathesis are known and comprise homogeneous and heterogeneous catalyst systems. The catalysts suitable for preparing oligomer mixtures of the formula I are generally based on a transition metal of group VIb, VIIb or VIII of the Periodic Table, preferred catalysts being based on Mo, W, Re and Ru.
Suitable homogeneous catalyst systems are generally transition metal compounds which are able, where appropriate in combination with a cocatalyst and/or where appropriate in the presence of the olefin precursors, to form a catalytically active metal carbene complex. Systems of this type are described, for example, by R. H. Grubbs in Comprehensive Organomet. Chem., Pergamon Press, New York, Volume 8, page 499 et seq. (1982).
Suitable catalyst/cocatalyst systems based on W, Mo and Re may, for example, comprise at least one soluble transition metal compound and an alkylating agent. These include, for example, MOCl2(NO)2(PR3)2/Al2(CH3)3Cl3; WCl6/BuLi; WCl6/EtAlCl2(Sn(CH3)4)/EtOH; WOCl4/Sn(CH3)4; WOCl2(O-[2,6-Br2xe2x80x94C6H3])/Sn(CH3)4; CH3ReO3/C2H5AlCl2, and the last four mentioned are preferred for the process according to the invention.
Further transition metal alkylidene complexes suitable as metathesis catalysts are described by R. R. Schrock in Acc. Chem. Res., 23, (1990) 158 et seq. These are generally tetracoordinate Mo- and W-alkylidene complexes which additionally have two bulky alkoxy and one imido ligand. Preferably used for the process according to the invention are ((CH3)3CO)2Mo(xe2x95x90Nxe2x80x94[2,6-(i-C3H7)2xe2x80x94C6H3])(xe2x95x90CHC(CH3)2C6H5 and [(CH3)2C(CH3)O]2Mo(xe2x95x90Nxe2x80x94[2,5-(i-C3H7)xe2x80x94C6H3])(xe2x95x90CH(CH3)2C6H5).
The catalysts particularly preferably used as homogeneous metathesis catalysts are those described in Angew. Chem. 107 (1995) 2179 et seq. in J. Am. Chem. Soc. 118 (1996) 100 et seq., and in J. Chem. Soc., Chem. Commun., (1995) 1127 et seq. These include, in particular, RuCl2(xe2x95x90CHR)(PRxe2x80x23)2, preferably RUCl2(xe2x95x90CHC6H5) (P(C6H11)3)2, (xcex76-p-cymene)RuCl2(P(C6H11)3)/(CH3)3SiCHN2 and (xcex76-p-cymene)RuCl2(P(C6H11l)3/C6H5CHN2. The two last-mentioned are generated in situ from one mol equivalent of (xcex76-p-cymene)RuCl2(P(C6H11)3) and 3 mol equivalents of diazoalkane ((CH3)3SiCHN2 or C6H5CHN2).
Suitable heterogeneous catalyst systems generally comprise a transition metal compound on an inert carrier, which compound is able to form a catalytically active alkylidene complex without cocatalyst, by reacting with the olefin precursors. Preferably used for this purpose are Re2O7 and CH3ReO3 on Al2O3 as carrier material.
The abovementioned homogeneous and heterogeneous catalyst systems differ greatly in their catalytic activity, especially with regard to cross-metathesis (step a)), and influence the product distribution in the cyclopentene-derived oligomer mixtures of the formula I. Thus, the ruthenium-based homogenous catalyst systems RuCl2(xe2x95x90CHC6H5) (P(C6H11)3)2, (xcex76-p-cymene)RuCl2(P(C6H11)3)/(CH3)3SiCHN2 and (xcex76-p-cymene)RuCl2(P(C6H11)3)/C6H5CHN2 are particularly suitable.
In this connection, the first-mentioned ruthenium complex displays higher catalytic activity than the two last-mentioned, which, with reaction conditions which are otherwise the same, results in increased cross-metathesis, with liberation of ethene to some extent too, and the resulting cyclopentene-derived oligomer mixture of the formula I thus having a somewhat smaller proportion of double bonds, which is manifested, for example, by a lower iodine value. In addition, owing to the cross-metathesis, a larger number of acyclic olefins without terminal double bonds is available, so that using the first-mentioned homogeneous ruthenium catalyst results in more cyclopentene-derived oligomers of the formula I which have only one or no terminal double bond. The two last-mentioned ruthenium complexes have a somewhat lower catalytic activity than the one mentioned first, so that, using them in the process according to the invention, results in cyclopentene-derived oligomer mixtures of the formula I which have a higher proportion of double bonds and thus a higher iodine value and a larger proportion of terminal double bonds.
The heterogeneous catalyst systems also display the activity differences described above with the corresponding influence on the metathesis products. CH3ReO3 on Al2O3 as heterogeneous catalyst has a higher catalytic activity than the corresponding homogeneous catalyst system composed of CH3ReO3/(C2H5)AlCl2.
It is thus possible if desired to obtain cyclopentene-derived oligomer mixtures of the formula I with varying proportions of double bonds and varying proportions of terminal double bonds, depending on the catalyst used.
The cyclopentene oligomers of the formula I obtained in the described process have an iodine value of at least 250 g I2/100 g oligomers, preferably at least 300 g I2/100 g oligomers. The average molecular weight of the cyclopentene-derived oligomers is at least 274 g/mol, which corresponds to an average conversion of three cyclopentene units per oligomer, assuming chain termination by an acyclic pentene (and not by a cross-metathesis product) in this case.
a) Hydroformylation
The process according to the invention for preparing functionalized cyclopentene-derived oligomer mixtures by reacting the previously described oligomers of the formula I which contain ethylenic double bonds comprises initially preparing hydroformylated oligomer mixtures by reacting the oligomer mixtures of the formula I with carbon monoxide and hydrogen in the presence of a hydroformylation catalyst.
Suitable catalysts for the hydroformylation are known and generally comprise a salt or a complex compound of an element of group VIII of the Periodic Table. Salts, and, in particular, complex compounds of rhodium or of cobalt are preferably used for the process according to the invention.
Examples of suitable salts are the hydrides, halides, nitrates, sulfates, oxides, sulfides or the salts with alkyl- or arylcarboxylic acids or alkyl- or arylsulfonic acids. Examples of suitable complex compounds are the carbonyl compounds and carbonyl hydrides of said metals, and complexes with amine, triarylphosphine, trialkylphosphine, tricycloalkylphosphine, olefins, or dienes as ligands. It is also possible to prepare catalyst systems in situ from the abovementioned salts and said ligands.
Suitable alkyl radicals in the ligands are the above-described linear or branched C1-C15-alkyl, in particular C1-C5-alkyl, radicals. Cycloalkyl is preferably C3-C10-cycloalkyl, in particular cyclopentyl and cyclohexyl, which may also be substituted by C1-C4-alkyl groups. Aryl is preferably phenyl (Ph) or naphthyl, which is unsubstituted or substituted by 1, 2, 3 or 4 C1-C4-alkyl, C1-C4-alkoxy, eg. methoxy, halogen, preferably chlorine, or hydroxyl, which may also be ethoxylated.
Suitable rhodium catalysts and catalyst precursors are rhodium(II) and rhodium(III) salts such as rhodium(III) chloride, rhodium(III) nitrate, rhodium(III) sulfate, potassium rhodium sulfate (rhodium alum), rhodium(II) and rhodium(III) carboxylate, preferably rhodium(II) and rhodium(III) acetate, rhodium(III) oxide, salts of rhodium(III) acid and trisammoniumhexachlororhodate(III).
Also suitable are rhodium complexes of the formula RhXmL1L2(L3)n where X is halide, preferably chloride or bromide, alkyl- or arylcarboxylate, acetylacetonate, aryl- or alkylsulfonate, in particular phenylsulfonate and toluenesulfonate, hydride or the diphenyltriazine anion, L1, L2, L3 are, independently of one another, CO, olefins, cycloolefins, preferably cyclooctadiene (COD), dibenzophosphol, benzonitrile, PR3 or R2P-A-PR2, m is 1, 2 or 3 and n is 0, 1 or 2. R (the R radicals can be identical or different) means alkyl, cycloalkyl and aryl radicals, preferably phenyl, p-tolyl, m-tolyl, p-ethylphenyl, p-cumyl, p-t-butylphenyl, p-C1-C4-alkoxyphenyl, preferably p-anisyl, xylyl, mesityl, p-hydroxyphenyl, which may also be in ethoxylated form, isopropyl, C1-C4-alkoxy, cyclopentyl or cyclohexyl. A is 1,2-ethylene or 1,3-propylene. L1, L2 or L3 are, independently of one another, preferably CO, COD, P(phenyl)3, P(i-propyl)3, P(anisyl)3, P(OC2H5)3, P(cyclohexyl)3, dibenzophosphol or benzonitrile. X is preferably hydride, chloride, bromide, acetate, tosylate, acetylacetonate or the diphenyltriazine anion, in particular hydride, chloride or acetate.
Particularly preferred rhodium complexes are Rh(CO)2acac and the rhodium carbonyl compounds such as tetrarhodium dodecacarbonyl or hexarhodium hexadecacarbonyl, which are used alone or together with phosphines. An Rh(CO)2acac/P(phenyl)3 catalyst is particularly preferably used, the molar ratio of the amounts Rh(CO)2acac to P(phenyl)3 being about 1:2 to 1:10.
Examples of suitable cobalt compounds are cobalt(II) chloride, cobalt(II) sulfate, cobalt(II)nitrate, their amine or hydrate complexes, cobalt carboxylates, such as cobalt acetate, cobalt ethylhexanoate, cobalt naphthoate and the carbonyl complexes of cobalt such as dicobalt octacarbonyl, tetracobalt dodecacarbonyl and hexacobalt hexadecacarbonyl. Preferably used for the process according to the invention are the cobalt carbonyl complexes and, in particular, dicobalt octacarbonyl.
Said compounds of rhodium and cobalt are known in principle and are adequately described in the literature or they can be prepared by the skilled worker in a similar way to the compounds already known. This preparation may also take place in situ, in which case the catalytically active species can also be formed from the abovementioned compounds as catalyst precursors only when the hydroformylation conditions are applied.
The hydroformylation catalyst is generally used in amounts of from 1 to 150 ppm, preferably 1 to 100 ppm. The reaction temperature is generally in the range from room temperature to 200xc2x0 C., preferably 50 to 150xc2x0 C.
The reaction can be carried out under a pressure of from about 10 to 650 bar.
It is possible according to the invention to use as hydroformylation catalyst a Rh(CO)2acac/P(phenyl)3 catalyst where the molar ratio of the amounts of Rh(CO)2acac to P(phenyl)3 is about 1:2 to 1:10, preferably about 1:3 to 1:7. Compared with hydroformylation catalysts without phosphine substituents, rhodium-triphenylphosphine catalysts permit reactions to be carried out at lower temperatures and under lower pressures, with involvement preferably only of terminal double bonds. The reaction temperature with this catalyst system is about 80 to 120xc2x0 C. under a pressure of about 1 to 30 bar.
The H2:CO molar ratio of amounts is generally about 1:5 to about 5:1.
The invention furthermore relates to the hydroformylated cyclopentadiene-derived oligomer mixtures obtained by the process according to the invention. The resulting hydroformylated oligomers have a carbonyl value of, preferably, at least 150 mg, in particular 250 mg, KOH/g product preferably at least 300 mg KOH/g product. It is preferred for most of the ethylenic double bonds present in the precursor to be converted by the hydroformylation into aldehydes or, as stated hereinafter, where appropriate also into alcohols, so that the iodine value of the hydroformylated oligomers is preferably xe2x89xa660 g I2/100 g oligomers.
The hydroformylated oligomers are advantageously liquid, owing to their lower degree of polymerization, and, in contrast to the hydroformylated polypentenamers described in the Journal of Polymer Science, Polymer Chemistry Edition 18 (1980) 781 et seq., show less of a tendency to crosslinking. The hydroformylation products thus retain their solubility in organic solvents.
The invention further relates to the use of the hydroformylated cyclopentene-derived oligomer mixtures as intermediates for further processing by functionalization of at least some of the aldehyde functionalities present therein.
The hydroformylated oligomer mixtures are furthermore suitable for modifying polymers, eq. as crosslinkers, as additives in leather tanning, and as biocides.
b) Oxo Carboxylic Acids
The invention further relates to a process for preparing cyclopentene-derived oligomer mixtures with carboxyl functionalities, where the previously described hydroformylated oligomer mixtures are reacted in the presence of an oxidizing agent.
It is generally possible to use a large number of different oxidizing agents and processes for oxidizing aldehydes to carboxylic acids, as described, for example, in J. March, Advanced Organic Chemistry, published by John Wiley and Sons, 4th Edition, page 701 et seq. (1992). Examples include oxidation with permanganate, chromate, etc. In a preferred embodiment of the process according to the invention, atmospheric oxygen is used to oxidize the hydroformylated cyclopentene-derived oligomer mixtures. Oxidation with air can take place either catalytically in the presence of metal salts or else in the absence of catalysts. The metals preferably employed are those able to change valency, such as Cu, Fe, Co, Mn etc. Preferably no catalyst is used in the process according to the invention. Oxidation with atmospheric oxygen can take place in a neutral or acidic medium and preferably takes place in the process according to the invention in an alkaline medium with addition of a base such as NaOH, KOH etc. It is easily possible in atmospheric oxidation to control the conversion by the reaction time. The oligomer mixtures with carboxyl functionalities preferably obtained on use of an oxygen-containing gas as oxidizing agent have an acid value of at least 50 mg KOH/g product, preferably at least 70 mg KOH/g product.
In another preferred embodiment of the process according to the invention, an aqueous hydrogen peroxide solution is used in combination with a carboxylic acid, preferably acetic acid, as oxidizing agent. This results in oligomer mixtures with carboxyl functionalities with the acid value being at least 150 mg KOH/g product, preferably at least 200 mg KOH/g product.
The invention further relates to cyclopentene-derived oligomer mixtures with carboxyl functionalities which can be obtained by the processes described above. Their acid value is, as described above, at least 50 mg KOH/g product, but preferably at least 70 mg KOH/g product, depending on the reaction procedure.
The invention further relates to the use of the oligomer mixtures with carboxyl functionalities, which may also be esterified, in particular with C1-C18 alkanols, for preparing copolymers, as complexing agents, eg. as incrustation inhibitors, as surfactant component, as concrete plasticizer and for sea water desalination.
c) Oxo Alcohols
The invention further relates to a process for preparing cyclopentene-derived oligomer mixtures with hydroxyl functionalities, where the hydroformylated oligomer mixtures from stage a) are reacted with hydrogen in the presence of a hydrogenation catalyst.
Suitable hydrogenation catalysts are generally transition metals such as Cr, Mo, W, Fe, Rh, Co, Ni, Pd, Pt, Ru etc., or mixtures thereof, which may be applied, to increase the activity and stability, to carriers such as active carbon, alumina, kieselguhr etc. To increase the catalytic activity, Fe, Co and, preferably, Ni can also be used in the form of the Raney catalysts as metal sponge with a very large surface area.
Preferably used as catalyst for the process according to the invention for preparing oligomer mixtures with hydroxyl functionalities is Raney nickel.
The hydrogenation of the oxo aldehydes from stage a) preferably takes place at elevated temperatures under elevated pressure, depending on the activity of the catalyst. When Raney nickel is used as catalyst, the reaction is carried out at about 80 to 150xc2x0 C. under a pressure of about 50 to 350 bar.
In a particular embodiment of the process according to the invention, the preparation of the oligomer mixtures with hydroxyl functionalities takes place together with the hydroformylation in a one-stage reaction. This is done by reacting the cyclopentene-derived oligomer mixtures with ethylenic double bonds of the formula I with carbon monoxide and hydrogen in the presence of a hydroformylation catalyst which is also suitable for the further hydrogenation to give the oxo alcohols. In principle, all hydroformylation catalysts are also suitable for catalytic hydrogenations, but generally higher temperatures and/or higher pressures and/or longer reaction times, and a larger amount of catalysts, depending on the catalytic activity, are used than for hydroformylation on its own.
All the catalysts described in stage a) are suitable for the process according to the invention for hydroformylation with simultaneous hydrogenation. A cobalt carbonyl catalyst is preferably used, in particular Co2(CO)8. The reaction is generally, carried out at from 100 to 220xc2x0 C., preferably 150 to 200xc2x0 C., under a pressure of from 50 to 650 bar, preferably 100 to 600 bar.
Other processes can also be used to reduce the oxo aldehydes to the alcohols. These include, for example, reduction with complex hydrides such as LiAlH4 and NaBH4, reduction with sodium in ethanol by the Bouveault-Blanc method, and other known processes.
The invention further relates to the cyclopentene-derived oligomer mixtures with hydroxyl functionalities obtained by one of the two processes described above. Conversion is preferably as complete as possible, ie. reduction is as complete as possible so that the carbonyl value of the oxo alcohols obtained by the process according to the invention is small by comparison with the carbonyl value of the oligomeric oxo aldehydes employed as precursor. The maximum carbonyl value of the oxo alcohols is generally 20. The alcohol value is at least 150 mg KOH/g product, in particular 250 mg KOH/g product, preferably at least 300 mg KOH/g product.
The invention further relates to the use of the cyclopentene-derived oligomer mixtures according to the invention with hydroxyl functionalities, where appropriate after alkoxylation (etherification) or esterification thereof, in particular with a C1-C18 carboxylic acid, as plasticizer, reactive thinner, antifoam, adhesive additive and as polyol component for preparing polyurethanes.
d) Amine Synthesis
Hydrogenation of aldehydes and ketones in the presence of ammonia, primary or secondary amines results, through reductive amination, in the corresponding primary, secondary or tertiary amines, and intramolecular crosslinking with amino groups already converted. The invention thus relates further to a process for preparing cyclopentene-derived oligomer mixtures with amino functionalities, where the hydroformylated oligomer mixtures from stage a) or the oligomer mixtures with hydroxyl functionalities from stage c) are reacted with ammonia, a primary or secondary amine in the presence of an amination catalyst and of hydrogen.
The hydroformylated oligomer mixtures are preferably reacted with ammonia in the presence of hydrogen and a hydrogenation catalyst, resulting in oligomer mixtures with primary amino functionalities.
The preparation of amines from aldehydes or ketones can generally be carried out as a one-stage or two-stage process. In the two-stage variant, firstly a condensate is formed from ammonia, primary or secondary amines on the one hand and aldehydes on the other hand in a first reaction step, and is then hydrogenated in a second reaction step.
In a suitable embodiment of the two-stage process, the hydroformylated oligomer mixtures from stage a) are reacted with ammonia or amines of the formula R-NH2 where R is NH2, C1-C10-alkyl, C6-C20-aryl, C7-C20-arylalkyl, C7-C20-alkylaryl or an organosilicon residue having 3 to 30 carbon atoms, or with a reagent which liberates ammonia or amines, and subsequently hydrogenated.
Examples of suitable R radicals in the amines R-NH2 are NH2, the alkyl radicals mentioned above for the oligomers of the formula I, phenyl, naphthyl, p-tolyl, o-tolyl, xylyl and tri(C1-C10)alkyl-silyl such as trimethylsilyl, tert-butyldimethylsilyl or else triarylsilyl, for example triphenylsilyl, tri-p-tolylsilyl or trinaphthylsilyl.
Suitable reagents which liberate ammonia are in general all ammonium salts, preferably ammonium carbonate. Ammonium carbonate and, in particular, ammonia are preferably used for the two-stage process according to the invention.
The process according to the invention for preparing oligomer mixtures with amino functionalities is preferably carried out as one-stage process, in which case the hydroformylated oligomer mixtures from stage a) are reacted with ammonia, a primary or secondary amine in the presence of an amination catalyst and of hydrogen.
The hydroformylated oligomer mixtures are preferably reacted with ammonia in the presence of hydrogen and of an amination catalyst. Suitable amination catalysts for the one-stage and the two-stage process are the hydrogenation catalysts described above in stage c), preferably copper, cobalt or nickel in the form of the Raney metals or on a carrier, and platinum.
Particularly suitable amination catalysts are the catalysts described in EP-A 394 842 and in DE-A 4 429 547 for hydrogenation of unsaturated compounds, which are incorporated herein by reference. This catalyst has, in the non-reduced oxide form, a content of from 20 to 75% by weight of nickel oxide, 10 to 75% by weight of zirconium dioxide and 5 to 50% by weight of copper oxide, with or without up to 5% by weight of molybdenum oxide and with or without up to 10% by weight of manganese oxide. Before being used according to the invention, the catalyst is subjected to a reductive treatment with hydrogen at from 180 to 300xc2x0 C. for from 5 to 30 hours under a hydrogen pressure of from 1 to 300 bar. The hydrogenation catalyst particularly used for the process according to the invention comprises 51% by weight NiO, 17% by weight CuO, 31% by weight ZrO2 and 1% by weight MoO3, based on the non-reduced oxide catalyst.
The reductive amination using the catalyst described above is carried out at from about 100 to 250xc2x0 C., preferably 150 to 230xc2x0 C., under a pressure of from about 100 to 300 bar, preferably from 150 to 250 bar.
It is possible if desired also to use other reduction processes to prepare the cyclopentene-derived oligomer mixtures according to the invention with amino functionalities from the oxo aldehydes of stage a). These include, for example, reductive amination of aldehydes in the presence of formic acid by the Leuckart-Wallach method, and other processes known to the skilled worker.
The invention further relates to the cyclopentene-derived oligomer mixtures with amino functionalities obtained by the process according to the invention. Conversion in the reductive amination in stage d) is preferably as complete as possible so that the resulting products have a small carbonyl value of, preferably, less than 20. The side reaction with formation of alcohols due to the oxo aldehydes undergoing reduction exclusively is of only minor importance in the process according to the invention so that products with an alcohol value of less than 40 mg KOH/g product are obtained. The amine value is at least 150 mg KOH/g product, preferably at least 200 mg KOH/g product. The tertiary amine content is moreover low with an amine value not exceeding 20 mg KOH/g product.
The invention further relates to the use of the cyclopentene-derived oligomer mixtures with amino functionalities according to the invention as component in epoxy resins, polyamides, polyurethanes, polyureas, as dispersant, dye transfer inhibitor, paper auxiliary, soil remover, component in skin creams and hair-care compositions, crosslinker for adhesives, stabilizer for polyoxymethylene, corrosion inhibitors, textile assistants, auxiliaries for dispersions, adhesives, protective colloids, adhesive coatings, epoxy hardeners in aqueous dispersions, auxiliaries for dishwashing compositions, paper auxiliaries, leveling agents for textiles, solubilizers for cosmetics, for metal extraction, comlexing agents, fuel additive, lubricants, corrosion inhibitor for aqueous systems, addition to glue and resin raw materials, dye fixation on textiles, paper fixation, retention, complexing agent for metal recycling, stabilizer for hydroxylamine, surfactants.
The invention is illustrated by means of the following non-restrictive examples.